Method for providing power plant maintenance services

ABSTRACT

An objective is to quickly provide appropriate maintenance services at low costs during routine inspection procedures and/or upon occurrence of abnormal events at thermal power plants or stations. In a thermal power plant maintenance system comprising a control device  1  for control of operation conditions and process amounts of plant equipment and a maintenance tool  2  operatively linked to the control device  1  via a network  7  for performing maintenance of a controlling controller  11  as built in the control device  1 , the system further comprises a remote maintenance device  3  that executes similar functions to those offered by the maintenance tool  2  for bidirectionally transferring plant data along with data concerning the controlling controller  11 &#39;s status via a communications line  8  between the maintenance tool  2  and the remote maintenance device  3  to thereby provide maintenance services of the thermal power plant of interest.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This is a continuation of application Ser. No. 10/458,379 filedJun. 11, 2003, which is a continuation of application Ser. No.09/793,947 filed Feb. 27, 2001, the content of which is incorporatedherein by reference it its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates generally to a method for providingthermal power plant maintenance services and, more particularly, to athermal power plant maintenance service provision method adaptable foruse in routine inspection procedures and/or upon occurrence ofabnormality or aberrant phenomena.

[0004] 2. Description of The Prior Art

[0005] In thermal power stations or plants, in cases where certainabnormalities occur during routine inspection and/or in the in-use stateor alternatively monitoring is especially required in specific eventssuch as upon start- up/shut-down of a unit, some works should berequired including but not limited to control system adjustment,searching for a cause(s) of abnormality, making up a countermeasure, andpreparation of a search report. Traditionally, in regard to suchmaintenance services, an engineer working for a manufacturer, who hasreceived a request from a client (thermal power plant), goes to thepower plant for complete such tasks in situ.

[0006] The prior art suffers from a problem as to the difficulty ofexpediting the cause research procedure for obstruction recovery whenabnormalities occur during operation due to the fact that a time istaken for the maker's engineer to actually arrive at the power station.Another problem faced with the prior art is that the engineer's workingat the real cite accompanies extra costs including a visiting expense,resulting in an increase in inspection costs as a whole.

SUMMARY OF THE INVENTION

[0007] It is therefore an object of the present invention to provide anew and improved thermal power plant maintenance service providingmethod capable of offering prompt and adequate maintenance serviceabilities during routine inspection and upon occurrence of abnormalitiesat a thermal power station while reducing costs required therefor.

[0008] To attain the foregoing object, the present invention provides athermal power plant maintenance service provision method adaptable foruse with a system including a remote maintenance device for execution offunctions similar to those offered by a maintenance tool, the methodincluding the step of permitting a maintenance service providing personto makes use of the remote maintenance device as linked to themaintenance tool via communications lines for bidirectionallytransferring plant data and data as to a present state of a controllingcontroller between the maintenance tool and the remote maintenancedevice to thereby provide thermal power plant maintenance services.

[0009] As explained above, according to the present invention, itbecomes possible, by comprising remote maintenance apparatus forexecution of similar functions A to those offered by the maintenancetool while at the same time letting the maintenance service provideremploy the remote maintenance apparatus as linked via communicationslines to the maintenance tool in the power station, to remotely provideany required maintenance services including but not limited to test datasummary and evaluation results during routine inspection proceduresand/or search and investigation results in abnormality occurrenceevents, which in turn makes it possible to provide prompt and propermaintenance services at low costs in routine inspection events and/orabnormality occurrence events, thus enabling improvement in quality ofmaintenance services.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a diagram showing an overall configuration of a systemfor explanation of a thermal power plant maintenance service providingmethod in accordance with one preferred embodiment of the presentinvention.

[0011]FIG. 2 is a function diagram of a maintenance tool of thisinvention.

[0012]FIG. 3 is a function diagram of a remote maintenance device of theinvention.

[0013]FIG. 4 is a flow diagram of a routine inspection service of theinvention.

[0014]FIG. 5 is a diagram showing a sequence of examples of an operationon-screen display for editing and analysis of static characteristicstest data of the invention.

[0015]FIG. 6 is a diagram showing a sequence of examples of an operationdisplay image for editing and analysis of dynamic characteristics testdata of the invention.

[0016]FIG. 7 is a diagram showing a sequence of exemplary operationdisplay images for editing and analysis of load change test data of theinvention.

[0017]FIG. 8 is a diagram showing an exemplary operation display forpreparation of control parameter change instruction data of theinvention.

[0018]FIG. 9 is a diagram showing a sequence of some exemplary operationdisplay images for preparation of static characteristics test report ofthe invention.

[0019]FIG. 10 is a diagram showing a sequence of exemplary operationdisplay images for preparation of dynamic characteristics test report ofthe invention.

[0020]FIG. 11 is a diagram showing a sequence of exemplary operationdisplays for preparation of load change test report of the invention.

[0021]FIG. 12 is a flow diagram of a service upon occurrence of anoperation failure in the controller of the invention.

[0022]FIG. 13 is a diagram showing a sequence of exemplary operationdisplay images for error log information research and analysis of theinvention.

[0023]FIG. 14 is a diagram showing a sequence of exemplary operationdisplays for preparation of recovery work guidance data of theinvention.

[0024]FIG. 15 is a flow diagram of a service in control failure eventsof the invention.

[0025]FIG. 16 is a diagram showing a sequence of exemplary operationdisplays for preparation of a control failure research request of theinvention.

[0026]FIG. 17 is a diagram showing a sequence of exemplary operationdisplays for analysis of control failure event data of the invention.

[0027]FIG. 18 is a diagram showing a sequence of exemplary an operationdisplays for preparation of a control failure search report of theinvention.

[0028]FIG. 19 is a flow diagram of an ordinary event service of theinvention.

[0029]FIG. 20 is a diagram showing a sequence of exemplary operationdisplays for preparation of a monitor search request of the invention.

[0030]FIG. 21 is a diagram showing a sequence of exemplary operationdisplays for analysis of data in ordinary event data of the invention.

[0031]FIG. 22 is a diagram showing a sequence of exemplary operationdisplays for preparation of a monitor search report of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] One preferred embodiment of the present invention will now beexplained with reference to the accompanying drawings below.

[0033]FIG. 1 depicts an overall system configuration for explanation ofa thermal power plant service provision method in accordance with onepreferred embodiment of the instant invention. This system comprises apower station side facility, which includes a control device 1containing therein a built-in controlling controller 11 and a processsignal input/output device (transfer device) 12, and a maintenance tool2 for performing maintenance of the control device 1 and datasave/storage of process signals or the like, which tool is operativelyassociated with a signal transmitter 4 and thermocouple 5 for sendingforth electrical signals indicative of process amounts such as apressure and temperature or else toward the control device l through aPI/O device 13, an operation end 6 such as a valve and/or a controldrive being operatively responsive to receipt of more than one controlsignal from the control device 1 for controlling the process amountssuch as pressure and temperature or the like so that each stays at aprespecified value, wherein the control device 1 and the maintenancetool 2 are operatively connected to each other via a unit network 7. Themaintenance tool 2 consists essentially of a central processing device21, a communication device 22, a monitor 23, and a transfer device 24.Although not specifically depicted in FIG. 1, the unit network 7 isactually connected also to a controlling computer and a CRT operationapparatus or the like for use as an operator's operation terminal inaddition to the control device 1 and maintenance tool 2. The system ofFIG. 1 also comprises a maintenance service provider side facility,which includes a remote maintenance device 3 with functions foranalyzation and editing of data as sent from the maintenance tool 2 onthe power station side and those for a variety of kinds of services.

[0034] The maintenance tool 2 on the power station side and the remotemaintenance device 3 on the maintenance service provider side areoperatively connected together via a public communication line 8. Theremote maintenance device 3 consists essentially of a central processordevice 31, communication device 32, and monitor 33. Optionally themaintenance tool 2 and remote maintenance device 3 may alternatively beconnected together via dedicated or “private” communication lines otherthan public communications lines.

[0035] Functionality and operation of each device will next be set forthbelow.

[0036] As shown in FIG. 1, the control device 1 is constituted from thecontrolling controller 11 and transfer device 12 plus PI/O device 13 andis operable to perform, based on programs prestored in a memory withinthe controlling controller 11, control processing of process signalsindicative of pressures and temperatures as input from the transmitter 4and thermocouple 5 via the PI/O device 13 and those signals coming fromother control devices as input via the transfer device 12 and unitnetwork 7 to thereby output its control processing results toward theoperation end 6 through the PI/O device 13 for equipment control oralternatively output such results to other control devices and themaintenance tool 2 via the transfer device 12 and unit network 7.

[0037] As shown in FIG. 1 the maintenance tool 2 is configured from thecentral processor device 21, communication device 22, monitor 23, andtransfer device 24.

[0038] Functionality and operation of the maintenance tool 2 are shownin FIG. 2. At the maintenance tool 2 an input device (not shown) such asa keyboard or a pointing device called “mouse” is used to create andedit a control operation logic chart, wherein drawing data thus producedis compiled to generate object data, which will then be sent via thetransfer device 24 and unit network 7 toward the controlling controller11 within the control device 1 for storage into its built-in memory. Inaddition, the maintenance tool 2 also has a “parameter online tuning”function for inputting a parameter change instruction through manualoperation of the input device such as a keyboard or mouse and thenrewriting a control parameter(s) being presently stored in the memorywithin the controlling controller 11 via the transfer device 24 and unitnetwork 7 in an online fashion. Further, it has a data save/storefunction capable of inputting a signal being presently output from thecontrol device 1 via the unit network 7 and transfer device 24,temporarily storing the signal in the central processor device 21, andpermitting visual on-screen displaying of numeric values and/or trendgraphs based on an instruction from the input device such as a keyboardor mouse. Other functions of the maintenance tool 2 include an error logacquisition function for acquiring or fetching error log information assaved within the controlling controller 11 via the unit network 7 andtransfer device 24 in the event that a certain operation failure orobstruction takes place in the controlling controller 11. Additionallythe communication device 22 is operable to control communications withexternal equipment over the public communication line 8.

[0039] As shown in FIG. 1 the remote maintenance device 3 is structuredfrom the central processor device 31 and communication device 32 plusmonitor 33. The remote maintenance device 3 offers similar functionalityto that of the maintenance tool 2, thereby allowing a person expected toprovide maintenance services-say, maintenance service provider-who is ata remote location spaced far from the power station of interest toremotely execute any one of the functions of the maintenance tool 2 ofsuch power station in a remote control fashion. In addition thereto, theremote maintenance device 3 also has a function for adding any necessaryfunctions to maintenance services.

[0040] Functionality and operation of the remote maintenance device 3are shown in FIG. 3. The remote maintenance device 3 is designed toacquire from the maintenance tool 2 via the public communication line 8and communication device 32 over communications several data items(process signal data, control signal data, controlling controller errorlog, controlling controller object data, control parameters, etc.) thatthe maintenance tool 2 has received from the control device 1 and thensave them at a memory device. And it edits and/or processes such data ashas been gained from the maintenance tool 2 and saved at the memorydevice in a way conformity with the content of a maintenance servicebeing presently provided. The maintenance service provider then use theremote maintenance device 3 to thereby provide maintenance servicesincluding, but not limited to, analyzing the resultant edited/processeddata for preparation of maintenance work instruction data indicative ofcontrol parameter modification and/or obstruction recovery works,transmitting the data to the maintenance tool 2 via the communicationdevice 32 and public communication line 8, and preparing a report tosend forth report data toward the maintenance tool 2 via thecommunication device 32 and public communication line 8.

[0041] An explanation will next be given of a thermal power plantmaintenance service provision method adaptable for use with illustrativeembodiment of the invention. With regard to a periodic or “routine”inspection service as one practical example of a first maintenanceservice, its service provision method will be set forth below.

[0042] At thermal power stations, routine inspection must be done atspecified constant time intervals as defined under laws and regulationsconcerned. In routine inspection events, a trial operation known as“test run” is ordinarily carried out in addition to inspection andupdating adjustment of the equipment involved. During such test run avariety of tests are done, which typically include a staticcharacteristics test (test for recording and confirming various kinds ofprocess amounts under a constant load condition and then adjusting acontrol system based on the data thus obtained), dynamic characteristicstest (test for recording and verifying the influence of process amountchanges upon various process amount and for adjusting the control systembased on the resulting data), load change test (test for recording andconfirming various process amounts upon changing of the load and foradjusting the control system based on the data). The “routine inspectionservice” is such that these test data items thus obtained are all takeninto consideration for investigation, wherein data analysis and testreport preparation are expected to be remotely done by a maintenanceservice provider.

[0043] A method for providing the “routine inspection service” is shownin a flow diagram of FIG. 4. At a power station a various kinds of testsare carried out resulting in acquisition or “sampling” of materialprocess amount data (pressures and temperatures or the like) and controlsignal data (operation end's instruction values or else) at themaintenance tool 2 in such event. An operator or worker who is expectedto act as the maintenance service provider lets the remote maintenancedevice 3 receive such gained data via the public communication line 8and store or save the data in the memory device of remote maintenancedevice 3. The operator then edits and analyzes the stored data at theremote maintenance device 3. Practical contents of major process stepsin the flow of FIG. 4 will be explained with reference to FIGS. 5through 11 below.

[0044] See FIG. 5, which pictorially illustrates a typical example ofthe sequence of on-screen visual displays for manipulation or operationby the operator-say, “operator console” displays or “operation”displays-to be used during the static characteristics edit/analysisprocesses at the remote maintenance device 3. When the operator selectsan-image for use as visual mnemonics or “icon” indicative of “StaticCharacteristics Summary” in a routine service menu display 9 beingpresently displayed on the screen of a display unit and then selects“Data Edit/Analysis” on a static characteristics summary menu display91, the display image changes to visually indicate a staticcharacteristics data edit/analysis display 92. While letting a trendgraph of the test data be displayed on this screen, s/he attempts tosummarize data as to material parameters which include, inter alia, afuel amount, water feed amount and air amount at a certain load.

[0045]FIG. 6 shows an exemplary sequence of operation display imagesused using dynamic characteristics test data edit and analysis processesat the remote maintenance device 3. When the operator selects an icon of“Dynamic Characteristics Test Summary” in the routine service menudisplay 9 being presently displayed on the display screen and thenselects “Data Edit/Analysis” icon in a dynamic characteristics testsummary menu display 93, a visual display 94 indicative of several dataconcerning the dynamic characteristics data edit/analysis is displayedon the screen. While viewing a test data trend graph included in thisdisplay image 94, s/he executes a task for summarization of materialdata items as to change-with-time properties of a main vapor temperatureand main vapor pressure in case a constant amount of fuel is supplied.

[0046]FIG. 7 shows an exemplary sequence of operation display imagesused during load change test data edit and analysis processes at theremote maintenance device 3. When the operator selects an icon of “LoadChange Test Summary” in the routine service menu display 9 and thenselects “Data Edit/Analysis” in a load change test summary menu display95, the screen changes to visually indicate an on-screen image 95indicative of material data as to the load change test data edit andanalysis. Using this visual display containing therein a test data trendgraph, s/he summaries material data items as to deviation of the mainvapor temperature and main vapor pressure during certain load changetest procedure.

[0047] In case the maintenance service provider's test data analyzationexecuted in this way results in more than one control parameterbeing-found to be modified or updated, s/he prepares control parametermodification instruction data at the remote maintenance device 3 fortransmission to the maintenance tool 2 over the public communicationline 8.

[0048] See FIG. 8 which depicts an exemplary on-screen operation displayconcerning preparation of the control parameter modification instructiondata at the remote maintenance device 3. When the operator selects anicon of “Make Parameter Modify Instruction” in any one of the staticcharacteristics summary menu display 91, dynamic characteristics summarymenu 93 and load change test summary menu 95, the display screen changesto visually present a visual display 10 showing several data items usedfor preparation of a parameter modification/update instruction. Usingthis on-screen visual display, s/he inputs an operation macro withparameter update required and a present value thereof (a value asreceived from the maintenance tool 2 is displayed) along with anumerical value updated and then performs a transmission operation,causing the control parameter update instruction data to be sent forthtoward the maintenance tool 2 over the public communication line 8. Uponreceipt of the control parameter update instruction data, themaintenance tool 2 operates to visually display a control parameterupdate guidance in accordance with the content of such control parameterupdate instruction data on the screen of monitor 23 to thereby permit aworker who is responsible for facility adjustment at the power stationto make use of the parameter online tuning function of the maintenancetool 2 to thereby rewrite via the transfer device 24 and unit network 7in the online fashion the control parameter or parameters beingpresently stored in the memory of the controlling controller 11 indeference to the guidance displayed. Alternatively if the tuning isdirectly set up by a changeover switch or the like in the state ofallowance then the maintenance tool 2 automatically operates to rewritein online way such control parameter(s) in accordance with the contentsof the control parameter update instruction data. In addition, afterhaving analyzed the test data concerned, the maintenance serviceprovider prepares at the remote maintenance device 3 a test reportcontaining therein a data summary table and control parameter updatehistory, which will then be sent forth to the maintenance tool 2 overthe public communication line 8.

[0049]FIG. 9 shows an exemplary sequence of operation display images foruse during preparation of a static characteristics test report at theremote maintenance device 3. When the operator selects “StaticCharacteristics Summary” icon in the routine service menu display 9 andthen selects “Make Report” in the static characteristics summary menudisplay 91, then the screen changes to visually present a staticcharacteristics test report preparation display 97. Using this on-screendisplay the maintenance service provider attempts to prepare a report ofa prespecified format in which material data items such as the fuelamount, water feed amount, air amount and the like are summarized alongwith the resultant control parameter change/update history.

[0050]FIG. 10 shows an exemplary sequence of operation display image forpreparation of a dynamic characteristics test report at the remotemaintenance device 3. When the operator selects “Dynamic CharacteristicsSummary” icon in the routine service menu display 9 and then selects“Make Report” in the dynamic characteristics summary menu display 93,the screen changes to visually indicate a dynamic characteristics testreport preparation display 98. Using this visual display the maintenanceservice provider prepares a report of a specified format in whichmaterial data items as summarized through editing and analysis ofdynamic characteristics data such as for example variation properties orthe like of the main vapor temperature and pressure in case the fuelamount is kept constant in value are indicated along with the resultantcontrol parameter change/update history.

[0051]FIG. 11 shows an exemplary sequence of operation display imagesfor preparation of a load change test report at the remote maintenancedevice 3. When the operator selects “Load Change Test Summary” icon inthe routine service menu display 9 and then selects “Make Report” in theload change test summary menu display 95, the screen changes to visuallyindicate a load change test report preparation display 99. Using thisvisual display the maintenance service provider prepares a report of aspecified format in which major data items as summarized through editingand analysis of load change test data such as for example variationproperties or the like of the main vapor temperature and pressure duringcertain load change test procedure are indicated along with theresultant control parameter change/update history. At the maintenancetool 2, it performs hard copy production or printing tasks with orwithout saving the report data thus received.

[0052] An explanation will next be given of a method for providing aserve in the event that an operation failure or malfunction occurs atthe controller-say, “controller abnormality event serve” in thedescription-as a second maintenance service example.

[0053] In the event that an operation failure or obstruction occurs atthe control device 1 due to certain causes, it becomes difficult for thepower plant to perform any intended operations. To avoid this, it shouldbe required to promptly perform clarification of the cause of suchobstruction creation for recovery required. In particular, thecontrolling controller 11 and PI/O device 13 and the like making up thecontrol device 1 are inherently designed to employ highly preciseelectronics parts or components with complicated control operationprograms being prestored in the memory of controlling controller 11;accordingly, upon occurrence of such obstruction, a need arises fortechnical support as to investigation by experienced engineers orspecialists. The “controller abnormality event service” is such that inthe case of occurrence of an obstruction at the control device 1, anyrequired services typically including activities for inquiring into thecause(s) and giving an instruction as to an appropriate recovery methodare done by a person who is expected to work as the maintenance serviceprovider.

[0054] See FIG. 12, which shows a process flow of such method forproviding the “controller abnormality event service.” In case an erroroccurs at the controlling controller 11, an operator will become awareof the generation of abnormality at the control device 1, by means of analarm. And s/he uses the error log acquisition function of themaintenance tool 2 to gain error log information being presently savedwithin the controlling controller 11 via the unit network 7 and transferdevice 24. Alternatively, in case an error occurs at the controllingcontroller 11, the maintenance tool 2 automatically operates to generateand issue a signal indicative of such error occurrence at thecontrolling controller 11 and then send forth this signal toward theremote maintenance device 3 via the communication device 22 and publiccommunication-line 8. Upon receipt of the error occurrence signal, theremote maintenance device 3 transmits an error log extraction requestsignal to the maintenance tool 2 via the communication device 32 andpublic communication line 8. When receiving this error log extractrequest signal the maintenance tool 2 acquires based on the error logextraction function the error log information being presently savedwithin the controlling controller 11 via the unit network 7 and transferdevice 24. The error log information gained by any one of the aboveschemes will then be passed to the remote maintenance device 3 via thecommunication device 22 and public communication line 8. The maintenanceservice provider attempts to investigate the error log information asreceived by the remote maintenance device 3 for analyzation of an errorcause(s)-that is, judging whether the presently occurring error is dueto hardware malfunction or due to failures in control operationprograms. Practical contents of the process flow of FIG. 12 will beexplained in detail with reference to FIGS. 13-14 below.

[0055]FIG. 13 shows an exemplary sequence of operation display imagesfor use during error log information investigation/analyzation at theremote maintenance device 3. Upon selection of “Conform Error Log” iconin a controller abnormality event service menu display 11, the screenchanges to visually indicate an error log confirmation display 111. Itis thus possible for the maintenance service provider by viewinginformation displayed thereon to become aware of details of the errorcause(s) and operation failed parts or components. After clarificationof the error cause(s), the maintenance service provider prepares arecovery work guidance at the remote maintenance device 3, whichguidance will then be sent to the maintenance tool 2 over the publiccommunication line 8.

[0056]FIG. 14 shows an exemplary sequence of operation display imagesfor use during recovery work guidance data preparation at the remotemaintenance device 3. Upon selection of a “Make Recovery Guidance” iconin the controller abnormality event service menu display 11, the screenchanges to visually indicate a recovery guidance preparation. display112. Here, the maintenance service provider prepares a recoveryprocedure document while performing a transmission operation to transmitthe recovery work guidance data to the maintenance tool 2 over thepublic communication line 8. Upon receiving of the recovery workguidance data at the maintenance tool 2, recovery guidance informationis visually displayed on the monitor 23 in accordance with the contentof such recovery work guidance data, thus permitting more than oneworker at the power station to execute required tasks for recovery indeference to the guidance.

[0057] Next, regarding a “control failure event service” as a practicalexample of a third maintenance service, its service provision methodwill be explained below.

[0058] In the power plant, unwanted control failures can take place fromtime to time during operation due to the presence of some mechanicalfactors and/or inappropriate control parameters, which would result forexample in generation of an alarm when a vapor pressure or temperaturegoes out of its tolerance range or, alternatively, result in the plantstatus becoming unstable with an increase in difficulties ofcontinuation of automatic control operations. In such cases,investigation for cause clarification is required along with equipmentadjustment with or without adjusting the control parameters of thecontrol device 1. The “control failure event service” is such that uponoccurrence of a control failure or malfunction, the cause clarifyinginvestigation and adjustment for improvement are to be remotely done bythe maintenance service provider.

[0059]FIG. 15 shows a process flow of a method for providing such“control failure-event service.” Suppose that the vapor pressure ortemperature goes out of the initially established allowance range duringpower plant operation. In this case, let material data-e.g. the contentof an alarm along with process amount data (pressures and/ortemperatures) and control signal data (operation end instruction valuesor else)-be transmitted from the maintenance tool 2 toward the remotemaintenance device 3 over the public communication line 8. Alternativelyan operator inputs a control failure search request at the maintenancetool 2 and then sends forth the control failure search request and itsassociated data to the remote maintenance device 3 via the publiccommunication line 8. Practical contents of the process flow of FIG. 15will be described with reference to FIGS. 16-18 below.

[0060]FIG. 16 shows an exemplary sequence of operation display imagesfor use during preparation of a control failure search request at themaintenance tool 2. Upon selection of a “Request Control Failure Search”icon in a remote maintenance request menu display 12, the screen changesto visually indicate a control failure search request display 121. Anoperator working at the power station attempts to input information asto control failure contents and failure generation date and time or thelike and then perform a data send operation, causing control failuresearch request data to be sent forth toward the remote maintenancedevice 3 via the public communication line 8. The maintenance serviceprovider saves the received data and alarm content or control failuresearch request content in the memory device of the remote maintenancedevice 3, and then analyzes such saved data at the remote maintenancedevice 3.

[0061]FIG. 17 shows an exemplary sequence of major operation displaysfor use during analyzation of the control failure event data at theremote maintenance device 3. Upon selection of a “Data Search/Analyze”icon in a control failure event service menu display 13, the screenchanges to visually indicate a control failure event data search/analyzedisplay 131. With this on-screen visual display, the maintenance serviceprovider commands to visualize a trend graph of the control failureevent data as received from the maintenance tool 2 along with thecontrol failure content and alarm content for analyzation of the controlfailure cause(s) and then careful consideration of an appropriate remedyto be taken. After completion of data analysis, the maintenance serviceprovider, remotely prepares at the remote maintenance device 3 a controlfailure search report that summarizes therein modification of a controlparameter(s) or control circuitry and the control failure cause, whichreport is then sent to the maintenance tool 2 via the publiccommunication line 8.

[0062]FIG. 18 shows an exemplary sequence of operation display imagesfor use during preparation of the control failure search report at theremote maintenance device 3. Upon selection of “Make Search Report” iconin the visual display of control failure event service menu 13, thescreen changes to visually indicate a control failure search reportpreparation display 132. With this screen image, then maintenanceservice provider produces a report summarizing the control failurecause(s) and remedy plus updating of a control parameter(s) or controlcircuitry for improvement of such control failure. Upon receipt of thecontrol failure search report at the maintenance tool 2, a guidance forupdating the control parameter(s) or control circuitry is visuallydisplayed on the screen of the monitor 23 in accordance with the updatedcontent of the control parameter(s) or control circuitry as recited inthe control failure search report, thus permitting an operator workingat the power station to rewrite by use of the parameter online tuningfunction or control operation logic edit function of the maintenancetool 2 the object data being presently stored in the memory within thecontrolling controller 11 via the transfer device 24 and unit network 7in deference to the presently displayed guidance. Alternatively, if thetuning is directly set by a changeover switch or the like to the stateof allowance then the maintenance tool 2 automatically operates torewrite in online way the object data in accordance with the updatedcontent of the control parameter(s) or control circuitry. Additionallyat the maintenance tool 2, it performs printing and/or saving tasks ofthe control failure search report data thus received.

[0063] Next, in regard to an “ordinary event service” as a practicalexample of a fourth maintenance service, its service provision methodwill be set forth below.

[0064] Upon start-up and shut-down of the power plant's functionalunits, the operation status must be monitored more carefully than innormal operation events due to the fact that startup and shutdownprocesses of a variety of types of facility equipment along with plantstate variations overlap together. Additionally, in the case of coalcombustion plants which are in the mainstream of thermal power plants inrecent years, a change in kind of coal used as raw fuel material canresult in a significant change in burning or combustion state dependingon coal's components and properties, which would affect the plantoperation in a various ways. Other factors affecting the operationinclude age changes of a plant per se. Although these are not alwaysregarded as operation failures or malfunctions, they call for adjustmentof control systems on a case-by-case basis. The “ordinary event service”is such that in cases where operation state monitor or “watchdog” isespecially required such as in the events of startup of the unitsinvolved, operation interruption or “shutdown,” coal kind change, andchange with age, monitoring and evaluation are remotely done by anoperator who is expected to act as the maintenance service provider.

[0065]FIG. 19 shows a process flow of a method for providing the“ordinary event service.” In case an operator in a power station judgesthat the maintenance service provider's plant operation monitoring andcontrol system evaluation is necessary due to the unit operationstartup, shutdown, coal kind change and change with age, s/he inputs amonitor search request at the maintenance tool 2. Practical contents ofthe process flow of FIG. 19 will be explained with reference to FIGS.20-22 below.

[0066]FIG. 20 shows a sequence of exemplary operation display images forpreparation of such monitor search request at the maintenance tool 2.Upon selection of an icon of “Request Monitor Search” in the visualdisplay of the remote maintenance request menu 12, the screen changes tovisually indicate a monitor search request display 122. The powerstation operator inputs information including a monitor search contentand monitor search period and others and then performs data sendoperations thus causing the monitor search request data to be sent forthtoward the remote maintenance device 3 via the public communication line8. The maintenance tool 2 acquires process amount data (pressures andtemperatures) and control signal data (operation end instruction values)in accordance with the content of such monitor search request and thentransmits the data to the remote maintenance device 3 over the publiccommunication line 8. In responding thereto, the maintenance serviceprovider saves the received data and the monitor search request contentin the memory device of the remote maintenance device 3 for analyzationof such saved data at the remote maintenance device 3.

[0067]FIG. 21 shows a sequence of exemplary operation display images foranalysis of the ordinary event data at the remote maintenance device 3.When selecting “Data Search/Analyze” icon in the visual display ofordinary event service menu 14, the screen changes to present ordinaryevent data search/analysis display 141. With this visual display, themaintenance service provider commands to display a trend graph of thedata as received from the maintenance tool 2 along with the monitorsearch content and the like, then evaluates the data, and theninvestigates for determination of whether a need arises to modify orupdate the control parameter(s) or control circuitry. After havinganalyzed the data, the maintenance service provider prepares at theremote maintenance device 3 a monitor search report which summarizestherein data evaluation results and, if necessary, modified controlparameter(s) or control circuitry along with the ground(s) thereof, thens/he sends the report to the maintenance tool 2 via the publiccommunication line 8.

[0068]FIG. 22 shows a sequence of exemplary operation display images forpreparation of the monitor search report at the remote maintenancedevice 3. Upon selecting of “Form Report” icon in the ordinary eventservice menu display 14, the screen changes to visually indicate amonitor search report preparation display 142. With this image, themaintenance service provider prepares his or her report summarizingtherein monitor search contents and evaluation results thereof plus acontrol parameter change(s) or control circuitry change(s) in case suchis judged to be necessary. At the maintenance tool 2, upon receipt ofthe monitor search report, a guidance for updating a controlparameter(s) or control circuit(s) is visually displayed on the screenof monitor 23 in accordance with the control parameter/circuit changecontent as recited in the monitor search report, thus permitting anoperator in the power station to rewrite using the parameter onlinetuning function or control operation logic edit function of themaintenance tool 2 the object data being presently stored in the memorywithin the controlling controller 11 via the transfer device 24 and unitnetwork 7 in deference to the presently displayed guidance.Alternatively, if the tuning is directly set by a changeover switch orthe like to the state of allowance then the maintenance tool 2automatically operates to rewrite in online way the object data inaccordance with the update contents of the control parameter(s) orcontrol circuitry. In addition, at the maintenance tool 2, it performsprinting and/or saving tasks of the monitor search report data thusreceived.

[0069] It has been described that with the illustrative embodiment, itis possible to promptly provide adequate maintenance services at lowcosts in routine inspection events and also in abnormality occurrenceevents thus improving the quality of maintenance services because of thefact that as far as the maintenance service provider is linked bycommunications lines with the maintenance tool in a power station, theuse of a remote maintenance device offering similar executable functionsto those of the maintenance tool makes it possible to provide from aremote cite various maintenance services including but not limited totest data summarization and evaluation results during routine inspectionprocedures and/or search and investigation results in abnormalityoccurrence events.

What is claimed is:
 1. A thermal power plant maintenance serviceprovision method for use with a thermal power plant maintenance systemcomprising a control device for control of an operation state andprocess amount of plant equipment and a maintenance tool operativelycoupled via a network to said control device for performing maintenanceof a controlling controller as built in said device, wherein the systemfurther comprises a remote maintenance device for executing a functionsimilar to that of said maintenance tool, and said remote maintenancedevice is operable to receive test data from said maintenance tool viasaid communication line, and wherein data of report summarizing thereinmonitor search content and evaluation is sent toward said maintenancetool via said communication line.
 2. The thermal power plant maintenanceservice provision method as recited in claim 1, providing a maintenanceservice wherein, upon occurrence of an obstruction at said controllingcontroller, said remote maintenance device receives error loginformation of said controlling controller from said maintenance toolvia said communication line, and wherein a maintenance service providingperson analyzes said error log information at said remote maintenancedevice to thereby prepare an obstruction recovery procedure, and whereindata of said obstruction recovery procedure is sent toward saidmaintenance tool via communication line to thereby visually display saidobstruction recovery procedure on a monitor of said maintenance tool. 3.The thermal power plant maintenance service provision method as recitedin claim 1, providing a maintenance service wherein, upon occurrence ofan obstruction at said controlling controller, said remote maintenancedevice receives from said maintenance tool via said communication line asignal indicative of an occurrence of an obstruction at said controllingcontroller, wherein an error log acquisition request signal of saidcontrolling controller is sent to said maintenance tool via saidcommunication line, and wherein, upon receipt of said error logacquisition request signal, said maintenance tool is operable toautomatically acquire the error log information of said controllingcontroller.
 4. The thermal power plant maintenance service provisionmethod as recited in claim 1, providing a maintenance service wherein,upon occurrence of an alarm due to plant control abnormality or uponissuance of a control failure search request through manipulation ofsaid maintenance tool, said remote maintenance device receives plantdata from said maintenance tool via said communication line, wherein amaintenance service providing person analyzes and evaluates said plantdata at said remote maintenance device for preparation of a report, andwherein data of said report is sent to said maintenance tool via saidcommunication line.
 5. The thermal power plant maintenance serviceproviding method as recited in claim 1, providing a maintenance servicewherein, upon issuance of a plant operation monitor search.requestthrough manipulation of said maintenance tool, said remote maintenancedevice receives plant data from said maintenance tool via saidcommunication line, wherein a maintenance service providing personanalyzes and evaluates said plant data at said remote maintenance deviceto thereby prepare a report, and wherein data of said report is sent tosaid maintenance tool via said communication line.
 6. The thermal powerplant maintenance service providing method as recited in claim 1,wherein the maintenance service providing person directly modifies morethan one control parameter and control circuitry within said controllingcontroller via said communication line and said maintenance tool andsaid network.
 7. The thermal power plant maintenance service provisionmethod as recited in claim 2, providing a maintenance service wherein,upon occurrence of an obstruction at said controlling controller, saidremote maintenance device receives from said maintenance tool via saidcommunication line a signal indicative of an occurrence of anobstruction at said controlling controller, wherein an error logacquisition request signal of said controlling controller is sent tosaid maintenance tool via said communication line, and wherein, uponreceipt of said error log acquisition request signal, said maintenancetool is operable to automatically acquire the error log information ofsaid controlling controller.
 8. The thermal power plant maintenanceservice providing method as recited in claim 2, wherein the maintenanceservice providing person directly modifies more than one controlparameter and control circuitry within said controlling controller viasaid communication line and said maintenance tool and said network. 9.The thermal power plant maintenance service providing method as recitedin claim 3, wherein the maintenance service providing person directlymodifies more than one control parameter and control circuitry withinsaid controlling controller via said communication line and saidmaintenance tool and said network.
 10. The thermal power plantmaintenance service providing method as recited in claim 7, wherein themaintenance service providing person directly modifies more than onecontrol parameter and control circuitry within said controllingcontroller via said communication line and said maintenance tool andsaid network.
 11. The thermal power plant maintenance service providingmethod as recited in claim 4, wherein the maintenance service providingperson directly modifies more than one control parameter and controlcircuitry within said controlling controller via said communication lineand said maintenance tool and said network.
 12. The thermal power plantmaintenance service providing method as recited in claim 5, wherein themaintenance service providing person directly modifies more than onecontrol parameter and control circuitry within said controllingcontroller via said communication line and said maintenance tool andsaid network.